Detect Fortinet Multiple Products Improper Verification of Cryptographic Signature (CVE-2025-59718) in IBM QRadar
Detects exploitation of CVE-2025-59718, an improper verification of cryptographic signature vulnerability (CWE-347) affecting multiple Fortinet products. This vulnerability, listed in CISA's Known Exploited Vulnerabilities catalog, allows attackers to bypass signature validation checks, potentially enabling unsigned firmware/software installation, man-in-the-middle attacks on update channels, or code execution with elevated privileges on affected Fortinet appliances.
MITRE ATT&CK
QRadar Detection Query
SELECT
DATEFORMAT(devicetime, 'yyyy-MM-dd HH:mm:ss') AS event_time,
sourceip,
destinationip,
devicevendor,
deviceproduct,
QIDNAME(qid) AS event_name,
UTF8(payload) AS raw_payload,
logsourcename(logSourceId) AS log_source
FROM events
WHERE
devicevendor ILIKE '%fortinet%'
AND (
UTF8(payload) ILIKE '%signature%fail%'
OR UTF8(payload) ILIKE '%unsigned firmware%'
OR UTF8(payload) ILIKE '%cert%verif%fail%'
OR UTF8(payload) ILIKE '%bypass%signature%'
OR (QIDNAME(qid) ILIKE '%firmware%' AND UTF8(payload) ILIKE '%error%')
OR (QIDNAME(qid) ILIKE '%update%' AND UTF8(payload) ILIKE '%invalid%')
)
AND LOGSOURCETYPENAME(devicetype) IN ('Fortinet FortiGate', 'Fortinet FortiManager', 'Fortinet FortiAnalyzer', 'Syslog')
LAST 24 HOURS
ORDER BY devicetime DESCQueries QRadar for Fortinet device events containing signature verification failures or unsigned firmware indicators over the past 24 hours.
Data Sources
Required Tables
False Positives & Tuning
- Verbose Fortinet debug logging enabled during troubleshooting that includes signature validation details
- Fortinet devices in HA failover scenarios generating signature-related events during sync
- Network packet capture devices mirroring Fortinet management traffic that include signature metadata
Other platforms for CVE-2025-59718
Testing Methodology
Validate this detection against 3 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1Simulate Fortinet Firmware Signature Bypass via Invalid Update Request
Expected signal: HTTP 400 or 403 response from Fortinet API with error body referencing signature validation failure; corresponding event in Fortinet system logs with type=event subtype=update level=alert
- Test 2Fortinet Management Interface Signature-Related Error Log Injection Test
Expected signal: Three syslog events appearing in SIEM with Fortinet device name, event type 'update' or 'system', and messages containing 'signature verification failed', 'cert verification failed', and 'unsigned firmware'
- Test 3Network-Level Simulation of Fortinet Update Channel Interception
Expected signal: Network flow logs showing Fortinet appliance connecting to update server via proxy; Fortinet logs showing certificate validation errors or signature failures when intercepted responses are presented
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